Boston vs Newton: PM2.5 compared
Over the last year, Boston's air was about 1.5× as polluted as Newton's: PM2.5 averaged 6.1 µg/m³ against 4.0, on the 200 days both cities were measured. Boston had the dirtier air on 169 of those days, Newton on 31. Boston was over the WHO's daily guideline of 15 µg/m³ on 5 of them, Newton on 8.
Right now
The last year, day by day
Month by month
Year by year
| Year | Boston | Newton | Days Boston was worse |
|---|---|---|---|
| 2026 so far | 36 | 23 | 117 |
| 2025 | 31 | 21 | 69 |
Means in US AQI over the days both cities were measured that year; a year shows once they share 30 such days.
Each city's worst days
Boston
- 18 Feb 20267723.2 µg/m³
- 6 Jan 20266516.5 µg/m³
- 17 Feb 20266516.5 µg/m³
Newton
- 18 Feb 202610235.9 µg/m³
- 18 Jan 20269834.3 µg/m³
- 6 Jan 20268828.8 µg/m³
Daily means in US AQI, with µg/m³ beside them, since the index stops at its top value, over the days both cities were measured in the last year. Each date opens that day's world board.
Compare either city with another
Boston
Side by side with Mecca (United States's worst on 30 days), Gujranwala (the world's worst on 30 days).
Newton
Side by side with Lexington (the nearest), Mecca (United States's worst on 30 days), Gujranwala (the world's worst on 30 days).
Use this page
SmogRank, PM2.5 daily means compared, Boston and Newton, 9 Oct 2025 – 8 Oct 2026, smogrank.com/compare/us-boston/us-newton (accessed 9 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
The same rules as every SmogRank figure: reference monitors first, and a day counts with 18 measured hours. How we measure.
Updated 2026-10-09 12:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); Love My Air (City and County of Denver), no reuse terms published (why we use them).